Can Vitamin A Prevent Lung Cancer?

Can Vitamin A Prevent Lung Cancer?

Seattle Post Intelligencer

Joe Petrowski, at high risk of lung cancer because of prolonged exposure to asbestos, is regularly taking Vitamin A and beta-carotene in the hope of lowering his cancer risk.

Petrowski, a retired Bremerton shipyard worker who now lives in Olalla, Washington is one of more than 18,000 people expected to take part in a nationwide research project to determine if vitamin A combined with its parent compound beta-carotene can help. prevent lung cancer - the leading killer of all cancers.

This unprecedented study, sponsored by the National Cancer Institute, is being directed by scientists at the Fred Hutchinson Cancer Research Center and the University of Washington.

The research recently entered its second phase and is seeking those at high risk for lung cancer to participate.

"This is the ultimate test in terms of preventing cancer," said Dr. Gary Goodman, a principal investigator for the study and a medical oncologist at Fred Hutchinson.

"A lot of health-food advocates have been promoting this for so long that people get skeptical," Goodman said. But the skeptics, including many in the medical community, are having to accept new evidence that points to the potent healing power of vitamins and certain nutrients.

Coincidentally, Petrowski is also a patient of Dr. Jonathan Wright, the Kent alternative physician whose clinic was the target of a dramatic raid by armed officers acting at the behest Of the Food and Drug Administration. Wright's clinic was raided because the FDA believed he was dealing in illegal vitamins and herbs.

Petrowski had called the clinic to pick up some allergy medication the day of the raid and was told police had seized the place.

"It seemed kind of crazy," he said. At Fred Hutchinson this week for a checkup, Petrowski chuckled at the apparent irony of one arm of the federal government encouraging people to participate in unproven vitamin therapy while another agency was aggressively trying to prevent it.

Medical researchers note that high doses of vitamin A, though not beta carotene, can be toxic. In high accumulation, it can cause damage to the liver, skin or nervous system.

Petrowski is among 1,700 people at high risk of lung cancer who volunteered for the first phase of the study and who are taking moderate amounts (30 milligrams of beta carotene and 20,000 units of vitamin A) of this vitamin compound to test for safety. No adverse reactions have been reported since the vitamin A project began in 1983.

The much larger second phase, only one year old, is called CARET, for Carotene and Retinol Efficacy Trial. it aims to answer by 1998, the question if lung cancers are being prevented by this vitamin compound.

Candidates for this phase of the study include people who may be at higher risk for lung cancer from smoking or exposure to potential carcinogens like asbestos.

"We're at the point of applying rigorous science to the whole area of nutrition and supplemental vitamins," said Dr. Gil Omenn, dean of the UW School of Public Health and Goodman's collaborator as the other principal investigator for the Vitamin A Project. Omenn began his work with Vitamin A focused on asbestos workers: Goodman came to the project concentrating on cigarette smokers.

A diagnosis of lung cancer today, Omenn said, offers a bleak survival rate of less than 15 percent. Yet he said there is ample and growing evidence from animal studies and human epidemiological work to indicate that vitamin A and beta carotene may significantly reduce the risk of lung cancer among those already at higher risk.

The Fred Hutchinson/UW study, like a national study of 8,000 people reported earlier that indicated high doses of vitamin C may significantly reduce the risk of heart disease, would be the first to conclusively show if a vitamin can prevent cancer.

Goodman and Omenn said the best scientific guess is that some vitamins and related chemicals like beta-carotene act to prevent cancer or heart disease by a process known as anti-oxidation.

Just as iron rusts through oxidation (a chemical reaction with oxygen), so can cells in the human body "rust" because of this chemical change. In this case, the rust is the formation of harmful oxidized chemicals in the body that are thought to lead to the unrestrained cellular growth found in cancer. Though much of this molecular activity is still not well understood, the researchers said indirect evidence indicates that beta-carotene and vitamin A can reduce this kind of harmful oxidation in the body.

Omenn said it will be about six more years before they can definitively say if the vitamin compound can prevent lung cancer.

The main obstacle beyond the complexity of the task, Omenn and Goodman agreed, is the pharmaceutical bias built into the medical research system.

"One of the problems in this is an economic issue," Goodman said. Much of medical research depends on financial support from drug companies or industry, he said. But these vitamins and natural products often can't be patented, Goodman noted, so private industry has little reason to fund studies of them.

Despite all these hurdles, the CARET study is plugging along with recruitment taking place in Seattle as well as Baltimore, San Francisco, Portland, Oregon and New Haven, Connecticut. Research subjects have already come from all over the United States, Canada and as far away as Japan.

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